Hammer adjusting means for pneumatic sheet metal flatteners



Feb. 28, 1939.

F. Jl HAUSCHILD HAMMER ADJUSTING MEANS FOR PNEUMATIC SHEET METALFLATTENERS Filed July 21, 1936 Patented Feb. 28, 1939 UNITED STATESPATENT ammo HAMMER ADJUSTING MEANS FOR PNEU- MATIC SHEET METALFLATTENEBS This invention relates to certain improvements in-the sheetmetal flattening mechanism which is described and illustrated in myapplication for patent, Serial No. 759,984, filed December 31, 1934, onPneumatic metal straighteners.

In the above named application I have illustrated a O-shaped yokecarrying at the end 01' one arm a dolly and at the end oi! the other arma pneumatic hammer supporting at its lower end an impact element struckby the hammer and projected against the work being flattened, the hammercasing carrying at its lower end a bell adapted. to contact with thework and acting to support the weight of the hammer casing on the 16work, instead of requiring the operator to exert his own strength tosupport the device and preventing or impeding any tendency of the hammerto tip laterally, thus again eliminating the strain on the operator dueto an attempt to hold the 20 hammer at all times at right angles to thework. The advantages of this structure are fully set forth in thespecification of the said application and need not be more specificallyadverted to herein:

v In this prior embodiment of my invention, it

was the dolly which was adjustable by means of a dolly supporting screwthreaded shank and by rotating this shank. the dolly was adjustabletoward or from the work. This is objectionable for two reasons; theshock of the blow on the sheet metal being flattened was received by therelatively light screw threads of the dolly shank which in-course oftime would tend to batter these threads somewhat and, in case themachine was operating on a relatively deep transversely curved fender ormudguard, thedolly could not be seen by the operator and it wasdiillcult to adjust the dolly or keep it in proper adjustment. Theoperator, under these circumstances, had to reach down 40 beneath thefender and operate the screw 01' the dolly without'actually seeing thedolly.

One object of the present invention, therefore,

is to provide means whereby the hammer 01 this mechanism with the bellattached thereto may be quickly adjusted toward or from the work and thedolly and locked in its adjusted position, this construction permittingthe use of relatively heavy threads on the hammer casing coacting with arelatively heavy screw threaded head mounted upon the corresponding armon the yoke and permitting the operator at all times to see theadjustment of the hammer and note that the work is held directly againstthe under face of the bell.

A further object of my invention is to provide means, by the adjustmentor the hammer, whereby a greater or less tension may be placed on theresilient yoke which supports the hammer at one end and the dolly at theother, and in this connection to provide for the adjustment of the ham.-5 mer in accordance with the amount of air pressure used so that thehammer may be screwed down until the yoke is under such tension as willhold the hammer to the work and under such tension that there shall beno "wok-back or m chatter.

A further object is to provide an internally threaded clamp which may betightened on the screw-threaded portion of the hammer to prevent thehammer working upward under the rapid vil5 brations to which it issubjected. This is particularly necessary as any slight fraction of aturn will put the hammer out of adjustment.

Still another object is to provide means which will permit the hammer tobe adjusted while the 20 machine is in operation.

A further object is to mount the dolly, not directly on the end of theyoke arm, as is shown in my prior application, but provide an extensionplug removably disposed in the dolly supporting 25 yoke arm and uponwhich the dolly itself is removably mounted so that with the plug anddolly removed, there will be a relatively wide space between theextremity oi the arm which would ordinarily support the dolly and thebell so that 30 the dolly supporting arm may be passed over doorpostsand the like structures where the metal 0! the door is to beflattened out and then the extension plug and the dolly be inserted ordisposed in place on the dolly supporting arm of the yoke. 35

A further object is to provide means whereby a relativelyelongated yokemay be used with its arms spaced relatively close together for useintaking out the dents in tender well skirts where 40 the ordinary yokeis impossible to use.

A further object is to provide means whereby the head with which thehammer casing has screw threaded engagement may be readily removed fromor applied to the hammer supporting 45 arm of the yoke.

Other objects will appear in the course or the following description. I

My invention is illustrated in the accompanying drawing wherein: 50

Figure l is a side elevation of a hammer casing and dolly constructed inaccordance with my invention and mounted upon the two arms of a yoke,

the complete yoke, however, not being illustrated in this figure.

Figure 2 isa vertical sectional view or the structure shown in Figure 1.

Figure 3 is a fragmentary transverse section through one form 01' dollyto show its connection with the supporting plug.

Figure 4 is a side elevation of a metal flattener constructed inaccordance with my invention and the yoke which is particularly designedto he used for operating on tender wells.

.Referring particularly now to Figures 1 and 2, ll designates the outercasing of a pneumatic hammer having therein a hammer (not shown) whichis reciprocated by pneumatic pressure; The upper end of this casing isshown as having a nipple ll having swivelled engagement with a couplingl2, the coupling having screw threaded engagement with an elbow ii inturn operatively connected to the flexible air hose ll which in turn isconnected to a source of air under pressure, the passage of the air tothe hammer being controlled by a foot valve, as shown in my priorapplication.

At the lower end or the hammer casing l0, there is disposed an impactelement It, as shown in my prior application, which is retracted bymeans or a spring IS. The impact element l5, as shown in dotted lines inFig. 2, has an upwardly extending stem which extends into the hammercasing 10, and is struck by the hammer therein.

The spring I is a contractile spring engaged at its, upper end with thehammer casing l0, and with its lower end coil engaged in a circumfer-'ential groove in the impact element IS. The hammer when it is projectedstrikes this impact element, drives it downward against the force of thespring l8, and the spring then immediately retracts the impact elementI5 to its initial position which is that shown in Figure 2. Carried onthe lower arm of the yoke i1 is a dolly I8 which confronts the impactmember l5. Adjustably mounted upon the smooth exterior face of thehammer casing it is a split collar l9 which may be clamped upon thehammer casing at any desired position by means of the clamp screw 20.This collar carries a resilient finger 2|. Below the collar and free forrotation upon the lower end of the hammer casing Ill is the tubularshank 22 of a bell 23. The tubular shank is cylindrical in form but theportion 23 which flares downwardly and. outwardly may be either annularin cross-section or semi-circular in cross-section. I have shown it inthe illustration as annular in cross-section. This bell extends outwardin all directions sufiilciently far from the impact element as to form afirm support for the hammer on the work and not only support the hammerso that the whole weight of the machine rests upon the work itself butalso suficiently to prevent the hammer from any tendency to tilt, thustaking the strain oil? the workman who otherwise would have to exertmanual strength to hold the hammer in a position at right angles to thework. The tubular shank 22 is formed with an annular groove 24 and theresilient finger 2i has a depression 25 engaging in this groove. Thisholds the bell from downward movement while permitting the bell torotate freely in both directions. The collar I9, after its adjustment,prevents the bell from moving upward at all. By adjusting the collar i9,therefore, the bell may be adjusted relative to the impact member i5 andshould be so adjusted that there is a slight space between the lower endof the impact element and the lower edge of the bell as illustrated inFigure 2. If the machine is operating on a crowned or upwardly auaoiocurved portion as, for instance, upon a transversely and longitudinallycurved fender, the bell should be adjusted slightly lower than it isinFigure 2, so that the impacting element will at all times be held apredetermined distance as, for instance, 36" or 1%" above the work untilit is struck by the hammer and driven downward.

So far, except for the swivelled connection of the hammer to the airpipe II, I have described and illustrated what is described andillustrated in my prior application. My particular improvement consistsin the instant case in providing the upper end of the hammer casing illwith the heavy and relatively quick screw threads 26 and providing ahead 21 mounted upon the upper arm of the yoke II, which head isinteriorly screw threaded to engage the threads 26. The head isrelatively long in comparison to the screw threads 26 and the screwthreads in the head are designated 28. This head 21 is a split head asshown in Figure 1, and on each side of the split the head is formed withthe two outwardly projecting lugs 29. A screw shown in dotted lines inFigure 1 and designated engages the interior screw threads of one ofthese lugs 29 and when the clamp screw is turned, the lugs are drawntogether to clamp the head upon the hammer casing Ill. When the screw isturned in the other direction, it releases this clamping action andpermits the hammer casing Hi to be rapidly rotated by hand to carry thecasing toward the dolly or away from the dolly. Preferably the screw 30is provided with a handle 3| whereby it may be quickly manipulated toclamp or unclamp the head from the casing. This head 21 is provided witha split socket 32, as shown in Figure 2, havthe impact member relativeto the axis of the shank which supports the dolly. The swivelledconnection between the coupling I 2 and the member I, or course, permitsthe rotation of the hammer casing relative to the air pipe.

The dolly l8, as shown in Figure 2, is formed on ,its underface with adownwardly flaring socket 3,6 and the lower arm of the yoke I! may beformed with a. rounded reduced portion to engage loosely in this socket.Preferably, however, and as shown more in detail in Figure l, I mountthe dolly 18 upon the reduced portion 3? of 'an extension plug 38 whoselowerend is reduced, as at 39, to fit within the tubular upper end ofthe lower arm of the yoke l1. By this construction the mechanism may bereadily put in position so that the two arms of the yoke will embrace orbe passed over on each side of a door post'or like structure. If thedolly supporting arm of the yoke i1 directly engaged the dolly, therewould he a relatively small space between the bell 23 and the extremityof the dolly supporting arm and force would"have to be exerted toseparate the two arms of the yokes I particularly fitted for use inoperating on fender wells. The upper and lower arms of the yoke arerelatively close together, it will be seen, and the lower arm has ahorizontal socket in it for the reception of the plug 39 which carriesan outwardly projecting extension 38 turned up-' ward at its end todetachably engage with the socket in-the dolly [8. Otherwise than this,the construction shown in Figure 4 is precisely what is shown in Figures1 and 2. It will be seen that shank embracing the hammer casing, thelower' with the clamp socket 32 formed upon the head 21, that the hammercasing may be readily connected to any desired form of yoke or any yokewhich may be necessary for a particular piece of work and that the yokein turn may have mounted upon it any form of dolly, there being dolliesof various different characters depending upon the character of the workto be done.

Preferably the head 2']? will be provided with an annular flange 28 atits lower end which will act as a stop limiting the inward movement ofthe hammer casing with reference to this head 2ll.

It is to be understood, of course, that many minor modifications mightbe made in the details of construction and arrangement of parts withoutdeparting from the spirit of the invention.

It is to be understood that the yoke is ordinarily made of malleableiron pipe and that as a consequence there is some resiliency in theyoke. In the operation of the device, by, screwing down on thehammer/casing it, it places this yoke under tension and the tensionpresses the bell against the work, thus the tool does not chatter orjump over the work. By my construction, the amount of tension placedupon it. s yoke by screwing down on the hammer canng may be verydelicately regulated. On light sheet metal, 30 or pounds of air pressureis used and on the average fender about or dopounds of air pressure isused and for medium heavy fenders, 120 or 125 pounds is used, and fortruck fenders as high as 225 pounds of air pressure is used. The higherthe air pressure used, the more tension must be placed upon the yoke byadjusting the hammer casing downward against the yoke to secure greatertension to hold the device upon the yoke.

It is to be understood that in Figures 1 and 2, the hammer casing it isillustrated in position before pressure is applied upon the work andthus upon the dolly to take the slack out of the arms of the yoke H.-When the bell 23 is moved downward, itengages the work, but to operatethe machine properly when air pressure is applied, the hammer casing itis to be screwed downwardly sufilciently to place the yoke undertension, as before stated.

Having described the structure and its ad-- vantages, what I claim is:-

1. In a sheet metal flattening mechanism, a hammer casing having apower-hammer therein and a spring retracted impact member carried by thelower end of the hammer casing and adapted to be struck by'the hammerand projected thereby, a downwardly flaring bell having a cylindricalends of the bell being normally disposed at a her, a yoke, a head andadapted to be struck predetermined distance below the impact memmountedupon one end of the yoke, the head embracing the hammer casing, the headbeing interiorly screw threaded and the hammer casing having threadscoacting therewith whereby the hammer casing may be adjusted bodilythrough the head, the other end of the yoke supporting a dollyconfronting the impact member, and means for locking the head upon thehammer casing when the harm mer casing has been adjusted.

2. In a sheet metal flattening mechanism, a hammer casing having ahammer therein, an impact member carried by the hammer casing by thehammer, a work engaging element carried by the hammer casing andextending normally bar, a resilient yoke'having one end engaged with thehammer casing, a dolly supported on the other end of the yoke and facingthe hammer casing, an interiorly threaded head on the other end ofthesubstantially U-shaped yoke, the threads being coarse and of relativelysteep pitch, the hammer casing at its upper end having threadsengagingthe threads of the head, the lower portion of the casing beingunthreaded, and means for clamping the casing in adjusted positionwithin the head.

3. In a sheet metal flattening mechanism, a hammer casing having ahammer therein, a impact member carried by the casing and struck by thehammer, a work engaging element carried by the hammer casing andextending normally below the impact member and adapted to rest upon thework, a resilient substantially U-shaped yoke, an interiorly threadedlongitudinally split head on one end of the yoke, the threads beingcoarse and of relatively steep pitch, the hammer casing at its upper endhaving threads engaging the threads of the head, the lower portion ofthe casing being smooth and unthreaded, the head on each side of thesplit therein having outwardly projecting lugs, a screw engaging saidlugs to clamp the head upon the hammer casing and a dolly supported onthe other end of the yoke. a

i. In a sheet metal flattening mechanism, an approximately U-shapedresiliently yieldable yoke, a hammer casing, a work-engaging membercarried by but extending below the hammer casing, a headmounted on onearm of the yoke and having relatively coarse screw threads of relativelysteep pitch, the hammer casing having threads engaging the threads onthe head whereby the hammer casing may be rotated to quickly adjust ittoward or from the other arm of the yoke, means for locking the hammercasing in any adjusted position, and a dolly supported on the other armof the yoke and facing the hammer casing.

5. A sheet metal flattening mechanism including an approximatelyU-shaped resiliently yieldable yoke, a hammer casing having an impactmember, a work-engaging member carried by but extending below the hammercasing, an interiorly threaded split head carried uponone end of theyoke, the threads being relatively coarse and of steep pitch, theexterior of the hammer casing having threads engaging the threads of thehead, means for clamping the split head tight upon the hammer casing tolock the by the other end of the yoke and facing the workengagingmember.

6. A sheet metal flattener, includinga substanbelow the impact memcasingagainst movement after adjustment, and a dolly carried it may be clampedupon the yoke, a work-engaging member carried upon one end of thecasing, and projecting below the latter and adjustable longitudinally ofthe casing, and a. dolly on the other end of the yoke and confrontingthe workengaging member.

FREDERICK J. HAUSCHILD.

